Scouring powders are among the oldest and, even today, still indispensable cleaning materials, which are used both in kitchens and in industries for removing obstinate soils. The basic constituents of scouring powders are, on one hand, the abrasive particles required for mechanically loosening obstinate soil and, on the other hand, surfactants as surface-active agents which are essential for the removal of greasy or fat-containing dirt. The scouring powders currently available in the market contain mostly alkylbenzene sulphonates as surfactants and, from case to case, other active substances and auxiliaries such as, for example, bleaches and disinfectants, zeolites and alkaline salts. German patent applications DE 2539733 A1 and DE 2739776 A1 (Procter & Gamble) describe scouring liquids and powders in which the abrasive consists of perlite in a quantity of up to 65%. These patents refer mainly to this special abrasive and mention sulfates and alkyl-benzene sulphonates as surfactants for the powders. Canadian Patent 1048365 (Procter & Gamble) describes abrasive powders having a high surfactant content of 20 to 35% and an abrasive content of 5 to 20% which are recommended both as scouring powders and an dishwashing detergents. A common feature of the scouring powders known from the literature and available in the market is that they have a good cleaning effect with respect to greasy and fat-containing soil, but foam to an undesirably high degree in use. To avoid foaming, attempts have even been made to market pure abrasives without any addition of surfactants. However, scouring powders such as these do not remove grease and in addition, behave totally unsatisfactorily in use because they cannot be dispersed. Hitherto, it has not been possible to satisfy consumer demand for low-foaming scouring powders with a good cleaning effect. In no case, fly ash was used as an abrasive. Fly ash, a primary product of coal utilization, is obtained as a fine particulate mineral residue, left behind after all combustibles in coal are burnt out. Its current output rate from steam raising and other plants utilizing pulverized coal, is about 100 million tones per annum. Its accumulation without adequate avenues for consumption or disposal otherwise, creates firstly the problem of space for its storage. Secondly, air polluted by its silica particles of less than 10 microns size emitted by boiler chimneys or carried away by prevailing winds from open heaps, causes breathing trouble to human beings. There is a pressing need felt by planners and operators of power stations, to search new areas of its usage, so that the twin problems of its storage and pollution could be mitigated to a considerable extent. Having no easy solution for transportation to outskirts, it is being piled up everyday. The subject of the invention is to prepare a scouring composition wherein the abrasive action of fly ash is utilized. Prior art search for fly ash based scouring powder compositions was made based on literature survey and patent databases, which did not yield any relevant references.
In U.S. Pat. No. 5,990,067 fly ash is not an essential component as it clearly and repeatedly states that the remainder of the formulation comprises any one out of: fly ash, port land cement, kiln dust or mixtures thereof. However in our case, fly ash is the main and essential ingredient, which acts as the abrasive agent.
In U.S. Pat. No. 5,990,067 quartz (in form of powdered quartz sand) is an active ingredient, which acts as abrasive agent. However in our case, the abrasive agent is fly ash instead of quartz, which is the most commonly used abrasive agent in convention scouring powders. Fly ash is a much more occupationally safer material than quartz as grinding quartz to desired fine size is an occupationally hazardous operation as it is associated with silicosis. Since fly ash is already in finely divided state, the hazardous operation of grinding is avoided. Thus in the case of the present invention fly ash is replacing quartz and not complementing it as is the case in U.S. Pat. No. 5,990,067. In the U.S. Pat. No. 5,990,067, fly ash if added is not an active ingredient but as a filler and weight increasing agent. However in our invention, fly ash is the main active ingredient while the rest provide supporting roles. In our case, we have not used any detergent in comparison to the referred patent.
The U.S. Pat. No. 5,990,067 is specifically meant for cleaning oil stains from concrete and asphalt surfaces, such as pavements, car parking lots, whereas the present invention is a hard scouring cleaning powder for cleaning burnt-on stains and dirt on metal surfaces such as scorch marks on a metal cooking utensil. The composition in the U.S. Pat. No. 5,990,067 is distributed on the oil stain on the concrete surface, dampened with mist of water and spread with only enough rubbing or mechanical action so as the formulation is worked into the pores and grains of the concrete surface. However in the case of the present invention, the burnt on stains and dirt is removed by the mechanical abrasive action of the abrasive agent (in this case fly ash) and the other ingredients of the composition playing a supportive role. Thus the referred patent is different from the present invention (fly ash based hard scouring cleaner) in terms of application, mode of application and composition. Therefore the present invention is totally different from the U.S. Pat. No. 5,990,067 in terms of application, mode of application and composition.